Restore User-Accessibility and Modifiability to Dynamic Functions

[jamesquilty]

In the previous version of Send Later, Dynamic Functions were stored in the filesystem as <profile>/sendlater3/ufuncs/*.slj files. It appears that under the current version Dynamic Functions are stored in <profile>/storage/default/moz-extension+++<uuid>^userContextId=<id>/idb/<id>.sqlite and the default functions are stored read-only within this database.

It would be great if Dynamic Functions, all of them, were accessible and modifiable by the user outside of the GUI as they were in the past (see use case in #421).

[jamesquilty]

Just following-up to indicate this is [still] important to me because the change to using a SQLite database now effectively requires me to manually create and update Dynamic Functions where previously I was able to automate this process. That feels like a backward step and restoring an ability for automatic updating of user scripts would certainly be a nice-to-have.

I'm grateful for the time the maintainers spend on the Send Later extension, thanks again for your efforts!